A Knowledge Base for Map Projection Selection

Choice of a suitable map projection is fundamental to map making and map use. The specification of a knowledge base used in an expert system for map projection selection is presented. The specification is developed on a "knowledge level" rather than "symbolic representation level." A knowledge level is the conceptual structure of the knowledge base, focusing on what knowledge should exist rather than how it should be represented. The conceptual structure can be used as a guide for choosing suitable knowledge representation constructs at the representation level. The conceptual structure for map projection selection knowledge is combined with map projection classification knowledge to provide context for projection selection. This context is part of the self-knowledge for the system that can be used to assist and explain the selection process. Conceptual graphs are used as a technique to specify the preliminary design of the knowledge base. Decision trees are used to specify the details of the knowledge framework as an ordered set of knowledge constructs. The specification has been implemented using production rules and frames, and is reported in a paper in press.